Hypodermic needle



Patented Dec. 8, 1925.

v NITED STATES ATENT OFFICE.

HERMAN TROPP, OF NEW YORK, N. Y., ASSIGNOR T0 WILLIAM IBRODY & (10., OF NEW YORK, N. Y.

rrrronnmvrro NEEDLE.

Application filed July 9,

To all whom it may concern.

-Be it known that I, HERMAN TRorr, citizen of the United States, and resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Hypodermic Needles, of whichthe following is a specification.

The usual typeof hypodermic needle consists of a tapered shank having a cylindrical hole parallel to its axis. At the tapered end there is inserted a tube-like needle, and

at the thickened end there is an inside cy lindrical recess which is threaded, the bottom of which is scooped out approximately semi-spherically, which is made necessary by the usual shape of the end of the boring instrument. This threaded shank is fastened to the neck of a syringe, which ends in a corresponding male thread. The union of the shank with the syringe must be leakproof. To attain this, since the thread is never tight enough to prevent leakage, a leather washer is placed between the threaded shank, and corresponding male thread of the syringe which ends in a flat surface. This washer has many disadvantages. It is not hygienic, it swells up, very often the shank with its sharpened end cuts into it, and destroys it, and it has to be renewed frequently. 1

In the needle and shank, which are the subjects of my invention, all such drawbacks are eliminated.

My invention will be best understood by means of the accompanying drawing, in which:

Figure 1 shows an elevation of the syringe and needle.

Figure 2 shows a longitudinal sectional view of the shank.

Figure 3 shows the tapered needle.

Figure 4: shows partial longitudinal enlarged section of syringe, shank, and needle.

Figure 5 is an end view of the shank and needle.

To avoid all disadvantages of the leather washer, the threaded part, (a in the shank of my needle is made short, and ends in a flat surface bottom (a so that the threaded shank, either directly, or through 1923. Serial No. 650,508.

a cylindrical metal washer (5 touches the flat surface at the bottom of the threaded male ending (0 of the syringe The leather washer is eliminated. Instead, the flat surface (a at the end of the threaded part (a of the, shank (0:) makes a contact with the tip of the male thread (0 of the syringe (c) the surfaces being very small, the least pressure will render the joint leak-proof.

As it is diflicult to cut the internal thread of the shank close to the flat bottom, the tip of the threaded male (0*) may not make the desired contact. To remedy this about 1/32" of the inside Wall of my needle is scooped out at the juncture of the flat bottom, forming a recess (0 which will afford the tip of the male thread to make a perfect contact, and render it absolutely leak-proof.

The old type of hypodermic needle which is soldered or swaged in the shank, is a very thin tube, with very thin walls. The diameter of the needle is of uniform thickness throughout the entire length of the needle. It is essential that the walls of the needle be very thin so that it may cause the least pain possible to the patient while being introduced into the soft tissues of the body at its periphery where the sensitiveness is greatest. Therefore the needle is very fragile, and. it is hard to introduce it in certain tough tissues of the body, such as ten-.

dons, periosteum, etc., and it also bends and breaks often, and is therefore dangerous to the patient.

The needle which is part of the object of my invention is a tube (6) with a very small canal of uniform diameter, but the walls of which are very thin at the end which is to pierce the tissues, and gradually having a threaded nipple, of a needle carryface of the recess, said fiat surface being ing shank having a threaded recess therein provided with a recess, and a washer adaptadapted to receive said nipple, said recess ed to be arranged therein. 10 ending in a fiat surface, and provided with Signed at New York, in the county of an annular groove immediately adjacent New York and State of New York, this 28th said fiat surface thereby allowing a perfect day of July A. D. 1922. contact between the nipple and the fiat sur- HERMAN TROPP. 

